Weather Radars are deployed in fixed-based and mobile networks to detect hazardous weather and provide advance warnings of approaching severe weather to people and their representatives, to industries for improved safety and performance, and to military and government entities for improved operations and risk abatement. The effectiveness of a single radar and a network or collection of radars is dependent on a number of factors that impact the operational performance of each radar system. Such factors include blockage of the radar beam by natural obstacles such as terrain and vegetation, blockage by manmade obstacles such as towers and buildings, attenuation of the radar signal by the atmosphere and its suspended contents, and beam propagation effects that bend the radar beam away from its normal expected path. Similar factors impact detection systems operating at the visible and infrared wavelengths, with said systems including video cameras and CCD arrays, and active laser range finding systems (lidar).
Methods and tools exist for determining the characteristics of single individual systems, or an effective coverage for a network of radar/detection systems. However, the resulting coverage for a planned network is typically derived by trial and error in the placement of the individual component systems. Such systems are often judged to be insufficient in performance due to gaps in coverage that are discovered after they are put into operation. The NWS employs the experimental method described by Leone (1989) in placing radar units which employs panoramic photography at each proposed site and at great expense.
The blocking of both active and passive signals by terrain is known as “occultation” or “shadowing”, and such concept can be applied throughout the electromagnetic spectrum from the subvisible and optical wavelengths to longer wavelengths associated with the X-band, C-band, and S-band radars. Shipley (2008) demonstrates the method and benefits for visualizing traditional 2-dimensional maps of occultation patterns as 3-dimensional displays using the Google Earth™ and ESRI ArcGlobe™ geobrowsers. Shipley (2009) goes further to show how individual occultation patterns for adjacent radars can be superimposed in a geobrowser to visualize the quality and effectiveness of an overlapping collection of radars. WxAnalyst (2011) subsequently developed a method to mosaic these individual occultation patterns to develop a quantitative estimate of the lowest observed altitude due to occultation by terrain for the radars when operating collectively. The composite field showing the lowest observed altitude Above Ground Level (AGL) due to occultation by terrain has become known as the “Shipley Floor.”
It would be advantageous to have a system and method for identifying gaps in a legacy radar system that also identified sites for additional radar equipment to be added to predictably fill the gaps and meet additional considerations relevant to the site and equipment selection decision.